When lithium based, nonaqueous electrolyte cells made with porous carbon black cathodes are discharged at low temperatures, the near surface regions of the cathode are primarily utilized. Cathode surfaces contain such pendant chemical functionalities as alcohol, carboxyl, carbonyl, or esters that can significantly impact the electrochemical kinetics of reduction reactions taking place at the cathode surface. This is because adsorption, charge transfer reactions, as well as acid base reactions that take place on cathode surfaces in addition to cathode surface conductivity may be modified by the presence of various functional groups on the cathode surface. The exact role of surface structure in controlling the performance of cathodes has been an important question. If cathode surface chemistries can be substantially modified, under-load voltages of cells discharged at high rates and/or low temperatures should be markedly altered.
Chemical or physical modification of porous carbon cathodes have long been the primary means of increasing cell capacities or under-load voltage of various lithium based oxyhalide cells. Approaches that have been used to improve cathode performance in lithium--sulfur dioxide cells, for example, have included: use of additives; catalysts; selection of carbon blacks with specific surface and/or bulk properties; using blends of various carbon blacks having synergistic properties; or soaking carbon blacks with various solvents to remove impurities. However, each of these methods suffer from one or more serious drawbacks and are therefore not widely used in Li/SO.sub.2 cell manufacturing.